Long-term supply of high bauxite

Calcined bauxite. Bauxite Brick general must go through before firing to obtain clinker, that barren of material. In this material as an ingredient in the aggregate, can ensure stable product size and dimensions accurate. China's bauxite, mostly D-K type, in the calcination process and subject to decomposition dehydration secondary mullitization and barite sinter three stages. (See bauxite) mineral calcined composition ratio according to different raw materials in the form of corundum Al2O3 and SiO2, mullite and glass phase. Bauxite is gray, pale yellow and dark gray. High bauxite is mainly used to produce high alumina refractories, also be used to make fused corundum. The two main factors that influence high sintered bauxite is mullitization and liquid secondary role. The former depends on Al2O3 / SiO2 ratio, the role played hinder sintering; sintering the latter play a catalytic role. In addition, Fe2O3 and TiO2 enter solid corundum and mullite lattice phase reaction, but also play a supporting role of sintering accelerator. In 1200 ~ 1400 ℃, the secondary mullitization cause swelling, sintering effect is a major obstacle; above 1400 ℃, the secondary mullitization reaction is substantially complete, the liquid crystal to promote the dissolution of a precipitation process, leading to densification, At this time, the main effect of promoting sintering. Ⅱ grade bauxite Al2O3 / SiO2 ratio is close to 2.55, just mullite area generates a secondary mullite maximum amount of stone, the hardest sintering. High levels of alumina sintering temperature as follows: Premium of 1600 ~ 1700 ℃, I level is 1500 ~ 1600 ℃, Ⅱ level is 1600 ~ 1700 ℃, Ⅲ level is 1500 ~ 1550 ℃. Calcined bauxite is usually kiln, shaft kiln, there is also down draft kiln calcination. High bauxite is based on Al2O3 content and Fe2O3, TiO2, CaO + MgO, K2O + Na2O and other impurities and clinker bulk density and water absorption and other indexes to classification.